Satellites in geostationary orbits are at virtually the same location relative to the earth, at points and times in the earth's rotation. Geosynchronous orbits require specified parameters (22,300 miles; 0° inclination) to make this work. Hence there is only one orbital track or “orbit” which can be used for a geosynchronous satellite. Within that orbit, there are only a limited number of available geostationary slots. However, the demand for satellite space increases in line with the demand for bandwidth. In recent years, demand for bandwidth has been increasing exponentially.
The arrangement that has been adopted over time uses multiple slots within the single ground track orbit, each slot having approximately 2 degrees of width relative to an earth-centered angle. This allows for communications with a minimum of electronic interference using directed antennae. The geo ring around the equator hence has a total of 180 slots (360 degrees divided by 2 degrees).
There are a limited number of geosynchronous slots that remain available.